Iran sits on a major throughway between what is now the world's No. 1 opium-producing nation, Afghanistan, and the markets of Europe. Iranian security forces clashed with narcotics smugglers nearly 1,500 times this past year. And the new use of drug-sniffing dogs, which are considered unclean by Muslims, is an indication of how seriously officials here take the drug war.

Iran's ruling clerics recently took the unprecedented step of issuing a fatwa, a religious edict, approving the use of dogs.

"Do you want to see the fatwa?" the uniformed dog handler asks the unsettled passenger. The man grabs his brief case and leaves. But several bags later, Hans, one of five dogs donated by the French government late last year, pounces on another bag. The face of its owner droops, as guards pull him aside and find a stash of opium.

The fatwa on dogs is one of several surprising steps taken by Iran - and matched by European donors, who have also provided bullet-proof vests - to stop the flow of drugs from Taliban-ruled Afghanistan, which last year doubled its poppy crop.

That, in turn, has made Iran the world leader in drug seizures, with the confiscation of 253 tons of narcotics last year. The 6 tons of heroin seized alone is equal to the entire annual street consumption of Britain and Italy.

Iran has demonstrated its commitment to stopping the flow - in both cash spent and lives of law-enforcement officers lost.

"Iran is extremely serious, but the extent of the problem is overwhelming them," says Neil Crompton, the deputy head of the British Embassy in Tehran.

So far, Britain has donated $2.5 million to Iran's drug-enforcement program, most of it through the UN Drug Control Program (UNDCP). The funds have been spent on, among other things, 1,000 bullet-proof vests and 170 sets of night-vision goggles, which - because of prohibitions on selling military equipment to Iran - required approval from the British Parliament.

"There has been a tangible change in the last six months, as people saw how serious the problem was," says Mr. Crompton. "These are not skirmishes - the [Iranians] are up against better armed forces, so we have asked other donors to keep an open mind about their needs.

"It's a big step for the Iranians too," he adds. "They have not cooperated with the outside world that much."

Some analysts suggest that if the US wanted to "break the ice" after its two-decade estrangement with Tehran - despite US accusations that Iran is a state-sponsor of terrorism - it could support the antidrug effort.

Though Iran is not known to produce narcotics itself, officials justify the $200 million annual budget of the drug-control programs by noting that there are as many as 1.5 million addicts in Iran, by UN estimates.

"We are convinced that we shouldn't allow this menace to go to other countries - our Islamic religion does not allow us to ignore the flow of drugs," says Esmaeil Afshari, head of the international-relations office of Iran's drug control headquarters. "But we have problems - how can we justify the cost to our people?"

Outside his offices, that cost is evident. There are a series of fading pictures of uniformed "martyrs," among 36 border guards killed in a battle last November.

The unit was cut off by 100 drug traffickers who were armed with heavy machine guns, rocket-propelled grenades, and mortars. Their slaughter - bringing Iran's total death toll in the drug wars to nearly 3,000 since 1979 - shocked the country.

"People ask: 'Why are you sacrificing our families and sons, for the Europeans?' " Mr. Afshari says. Security forces last year were engaged in 1,445 armed confrontations, with up to seven battles in a day.

While praising the UN and European donors, others could do more. "The US government is doing a lot for other countries, such as giving billions to Colombia," says Afshari. "They shouldn't ignore Afghan production."

During the reign of Shah Muhammad Reza Pahlavi, Iran was a major producer of drugs, and opium was openly available in pharmacies. Opium production in Iran was halted in 1979, after the Islamic Revolution.

The 1997 election victory of reform-minded President Mohamad Khatami ushered in a new era of transparency that helped expose Iran's domestic drug-abuse problem. "The drug issue is one that the government has pushed as hard as possible" says Antonio Mazzitelli, the UNDCP representative in Tehran. It's seen as a way to build bridges with the international community.

Foreign governments must tread a fine line in helping a nation widely identified in the West as a sponsor of terrorism. But few here question Iran's readiness, and point to the fatwa permitting Muslims to handle dogs as a sign of an interpretive, modern agility when it comes to Islamic strictures.

"They don't have a pet culture, and this is a country where for 2,000 years, the dog was supposed to be impure," says a senior European diplomat. "But here the dog is being used for a religious purpose, and in the Shiite Muslim tradition, there is a hierarchy of religious rules. They haven't said that it's OK to touch dogs, but ruled that it is more important to fight drugs."